The present invention relates to a spring mattress having elastic springs provided in a sheath and which are disposed in rows next to each other, and are fixed at both ends to stiffening grid, generally formed of metal.
The spiral springs of conventional spring mattresses are formed presently of steel. However, steel is rejected by some users of spring mattresses because low electrical currents can be induced therein which, in the view of these users, can have deleterious effects upon them. Instead of the spiral springs, the mattress sheath can be filled with a plastic foamed material, hair or straw, which permits to avoid the use of the electrically conducting steel. However, the special flexural effect, which is achieved by using prestressed steel helical springs is also eliminated.
Accordingly, an object of the invention is to create a spring mattress of the type described above which, while retaining the flexural effect inherent in helical springs, would not be susceptible to the inducement of an electrical current therein.